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Man and pig are almost brothers! What animals are most similar to people. Achievements of modern genomics. The similarity of a pig with a person What is common between a person and a pig

90% of discoveries in medicine are made thanks to laboratory rodents. It was they who became the first "tasters" of well-known medications, antibiotics were tested on them, thanks to them we learned how alcohol, drugs, radiation affect the human body ... Why rats?

What is similar: the rat surprisingly coincides with the man in the composition of the blood and in the structure of the tissues; the only animal that, like humans, has abstract thinking. It is the ability to draw conclusions that allows these animals to be so tenacious.

Pig

Fossil skeletons of large pig-headed lemurs, megaladapis, have been found on the island of Madagascar. Instead of pig hooves, they had a five-fingered "human" hand. There are far-reaching plans to be used as surrogate mothers to carry human embryos... sows.

What is similar: the pig embryo has the laying of a five-fingered hand and a muzzle similar to a human face - hooves and a snout develop only just before the very birth; the physiology of the pig most closely matches that of a human. It is not for nothing that pig organs can be used for liver, kidney, spleen and heart transplantation.

Dolphin

Professor A. Portman (Switzerland) conducted research on the mental abilities of animals. According to the results of the test, a man came out on top - 215 points, a dolphin was on the second - 190 points, an elephant was on the third place, and a monkey was on the fourth.

What is similar: humans and dolphins have the most highly developed brains. We have a brain weight of about 1.4 kg, theirs is 1.7, and in the same monkey it is three times less. The dolphin's cerebral cortex has twice as many convolutions as ours. Therefore, a dolphin is able to acquire 1.5 times more knowledge than a person.

great ape

There are four species of them: the largest and strongest is the gorilla, then the orangutan, the next largest is the chimpanzee, and finally the smallest is the gibbon.

What is similar: similar to the human structure of the skeleton; ability to walk upright; a thumb set aside (although not only on the hands, but also on the legs); life in the family, and, as a rule, the cub leaves only after meeting a potential spouse.

Fish

It would seem, where are we and where are the fish? We are warm-blooded. They are cold-blooded, we live on land, they live in water, but ...

What is similar: fish collagen (a protein that forms the basis of the connective tissue of the body - tendons, bones, cartilage, skin, providing its strength and elasticity) has a protein molecule almost identical to that of a human. This property is often used in cosmetology in the manufacture of cream.

More on the topic

6 myths about genes
The close relationship between pigs and humans, ethnicity embedded in the genes and other common misconceptions about genes

PostNauka debunks scientific myths and fights common misconceptions. We asked our experts to comment on the established ideas about the role of genes in the human body and the mechanisms of heredity.

Pig is genetically closest to humans

Mikhail Gelfand- Doctor of Biological Sciences, Professor, Deputy Director of the Institute for Information Transmission Problems of the Russian Academy of Sciences, member of the European Academy, laureate of the Prize. A.A. Baeva, member of the Public Council of the Ministry of Education and Science, one of the founders of Dissernet

It is not true.

This question is very easy to check: you just take the sequences of the genomes of humans and other mammals and see what they look like. No miracle happens there. Man is the most looks like a chimpanzee, then - the gorilla, other primates, then rodents. There are no pigs around.

If we consider this case, the result will be funny, because the closest relatives of the pig will be hippos and whales. This is a success of molecular evolutionary biology, because whales have changed so much that it was quite difficult to understand what they look like from morphological features.

A possible source of the myth could be that the pig lacks some of the proteins that make tissues recognizable by the human immune system. Pig organs are indeed the best among mammals adapted to transplant them to humans, especially if it is a genetically modified pig, in which some genes are additionally suppressed. Chimpanzees are more suitable, but no one will torture a chimpanzee to save a man.

In any case, "genetically" is not a very correct term. We can say, for example, that genetically cousins ​​are closer to each other than fourth cousins. When you compare animals that don't interbreed, there's no genetics involved. Genetics is a science that tells what happens in the offspring when two individuals are crossed. The correct term would be "phylogenetically", i.e. that which reflects ancestry. And from the point of view of common origin, the pig is closer to dogs than to people.

Genes determine all individual traits of a person

Maria Shutova— Candidate of Biological Sciences, Researcher at the Laboratory of Genetic Fundamentals of Cell Technologies, Institute of General Genetics of the Russian Academy of Sciences

This is true, but in part.

What matters is how these genes work, and many factors can influence this work. For example, individual differences in DNA sequence, so-called single nucleotide polymorphisms, or SNPs. About 120 of these SNPs distinguish each of us from parents, from brothers and sisters. There are also a large number of genome modifications, which are called epigenetic, that is, supragenetic, which do not affect the DNA sequence, but affect the work of genes. In addition, one cannot deny the rather large influence of the environment on the expression of certain genes. The most obvious example is identical twins, whose genome is as close as possible to each other, but we can see clear differences, both physiological and behavioral. This illustrates quite well the influence of the genome, epigenetics, and external environmental factors.

You can try to evaluate the contribution of genetics and external factors to the manifestation of a particular trait. If we are talking about some disease-causing mutations that lead to very severe genetic syndromes like Down syndrome, then the contribution of genes is 100%. For the "minor" breakdowns associated with Parkinson's, Alzheimer's, different types of cancer, there are estimates of how often people with a particular mutation manifest the corresponding syndrome, and they can vary from a few percent to several tens of percent. If we are talking about complex traits that include the work of many genes at once, such as behavioral characteristics, then this, for example, is influenced by the level of hormones, which can be genetically determined, but the social environment also plays a big role. Therefore, the percentage is not very clear and highly dependent on the specific feature.

This myth is partially true: everyone knows that we differ from each other in the DNA sequence, there are many popular science articles about the connection of a certain polymorphism (mutation) with eye color, curls and the ability to run fast. But not everyone thinks about the contribution of supragenetic factors and the environment to the expression of any trait, and besides, this contribution is quite difficult to assess. Apparently, this is the reason for the emergence of such a myth.

Genome analysis can reveal ethnicity

Svetlana Borinskaya

It is not true.

Belonging to a particular ethnic group is determined by culture, not genes. The family influences which ethnic group (or groups, if the parents have different ethnicity) a person belongs to. But this influence is determined not by genes, but by upbringing, the traditions of the society in which a person grew up, the language he speaks, and many other cultural features.

Of course, from parents, everyone receives not only language and education, but also genes. Which parental genes the child will get is determined by the fusion of the sperm and the egg. It is at this moment that the individual's genome is formed - the totality of all hereditary information, which, in interaction with the environment, determines the further development of the organism.

The processes of isolation of individual groups, interspersed with migrations and mixing of peoples, leave genetic "traces". If the number of marriages within a group exceeds the influx of genes from outside, then such a group accumulates gene variants that distinguish it from its neighbors in terms of spectrum and frequency of occurrence.

Such differences were revealed in the study of population groups living in different regions of the world and having different ethnicity. Therefore, genome analysis can show which group a person's relatives and ancestors belong to - if these more or less distant relatives have already been studied by population geneticists and if they indicated their ethnicity during the study. But this analysis does not indicate the nationality or ethnicity of the owner of the analyzed genome - this nationality may be the same as that of his relatives (especially if they are close relatives), but may be completely different.

nationality (or ethnicity) is not sewn into the genes, this phenomenon is not biological, but cultural. The times when it was believed that an ethnos has a biological nature are gone. Ethnicity, just like language, is not an innate feature - it is acquired (or not acquired) in communication with other people. The myth that "blood" or genes determine nationality (or any other traits formed under the influence of culture) is very dangerous. He was used more than once to manipulate public consciousness, the consequences of which ranged from different depths of discrimination to genocide.

All mutations are harmful

Anton Buzdin— Doctor of Biological Sciences, Head of the Group for Genomic Analysis of Cell Signaling Systems, Institute of Bioorganic Chemistry named after A.I. Academicians M. M. Shemyakin and Yu. A. Ovchinnikov RAS

It is not true.

Many mutations are indeed harmful, but not all. In particular, some mutations occurred in our common ancestor with chimpanzees, which led to the fact that we humans appeared. Whether this mutation is useful is a question.

Mutations for the organism itself can be beneficial, neutral or harmful. Most of the mutations are neutral. Then come the harmful ones, and a very, very small part can be considered useful. In particular, the difference between people in the human population on our planet, of course, is determined by a combination of some normal variants of genes, which are now called normal, but they arose at one time as mutations. Then these mutations took hold, and some of them are beneficial.

Damage to some genes can have unexpected positive consequences. For example, a person becomes resistant to certain pathogens, such as the human immunodeficiency virus. A classic example is sickle cell anemia, where hemoglobin is abnormally shaped. However, the presence of this mutation prevents infection with malaria, and therefore it has gained a foothold in Africa. People who do not have this mutation die, and those who have it get a chance to survive. On the one hand, this is a harmful mutation, but on the other hand, it is beneficial.

There are mutations that have changed the activity of certain metabolic enzymes, that is, proteins that are responsible for how our bodies metabolize milk, or fats, or alcohol, and so on. In different populations, there was a selection for some of these mutations, which are now considered normal variants (but once they were, of course, mutations), which led to the fact that, for example, the inhabitants of the north metabolize fat more actively than the inhabitants of the south . This is due, among other things, to survival in the conditions of the north. And Europeans and Asians are known to have different ethanol metabolism.

Different people have different genes

Inga Poletaeva— Doctor of Biological Sciences, Leading Researcher, Laboratory of Physiology and Genetics of Behavior, Department of Higher Nervous Activity, Faculty of Biology, Lomonosov Moscow State University. M.V. Lomonosov

This is true, but in part.

All the genes that make up the genome of any species have a similar function, a similar structure, and deviations in the structure of these genes can relate only to minor changes in the structure of the proteins and regulatory elements that these genes determine. Another thing is that some regulatory moments of turning genes on and off may differ. This may be the reason for differences between organisms.

One example is the rapid maturation of the CNS: some children can speak at almost two years of age, while others know only a few words at this time. Nerve cells that need to develop and connect with each other in a network do this in different people at different speeds. There are also rare events - the so-called mutations, which can actually make their host different compared to most organisms of this species. The mutant gene is the basis for the synthesis of the abnormal protein.

Sometimes such mutations affect the regulatory regions of genes, and either a gene turns on at the wrong time, or some other violations of its work occur. Thus, there are genes that, due to their "breakdowns", can cause changes in the structure of the proteins they encode. And these changes can turn out to be very important for the fate of a given organism, while both physical and biochemical abnormalities are detected.

But genome each species of animal (and plant) is the same in its fundamental features. Close species have a small number of differences, unrelated species differ more. However, the mouse is considered a convenient object of modern genetics because it has a very large part of its genes similar to human genes, yeast and roundworms differ much more strongly.

The genomes of individuals of the same species can indeed differ slightly in nucleotide composition. As a rule, this does not affect the function of the gene or affects little. However, differences that do not affect the functions of genes are of interest to geneticists, since they allow us to trace genetic changes in populations.

In biology there was a paradigm "one gene - one enzyme". This is one of the first concepts in developmental biology. But now it is clear that this is a simplified view, because there are genes that have only a regulatory function and encode simple protein molecules. Such genes are not well studied in all cases, and they are no less, and perhaps even more important for tracking the work of this entire complex system of genetic control of the development of an organism.

People easily believe in the myth that genes differ from person to person because they have heard that there are genes on which a lot depends, and that individual differences (and unexpected similarities) are facts of real life. However, between a gene (and even a protein that is “read” from this gene) and the signs of an organism that we encounter, there are many complex processes. This complex system is largely responsible for individual differences.

On the other hand, a person always wants to have an authoritative, close to peremptory and "scientific" opinion. In this regard, one has to hear phrases like "it has entered our genes." It’s not that easy to “enter” our genes, and into the genes of other organisms too.

Acquired traits are inherited

Svetlana Borinskaya- Doctor of Biological Sciences, Leading Researcher, Laboratory of Genome Analysis, Institute of General Genetics. N. I. Vavilov RAS

It is not true.

Biologists have thought so for a long time. The inheritance of acquired traits in the history of world science is primarily associated with the name of Jean Baptiste Lamarck (1744-1829). Lamarck's views on inheritance were also shared by Charles Darwin (1809-1882), who tried to combine them with his theory of the origin of species through natural selection. In Russian history, this idea is associated with the name of T.D. Lysenko (1898-1976). The discussion about the mechanisms of inheritance would have remained purely scientific, if not for the repression and destruction of geneticists who did not accept Lysenko's views. Therefore, the discussion of this topic, especially in Russia, is still often politicized.

The study of the molecular mechanisms of the operation of the hereditary apparatus showed that the level of activity of the genes that affect this trait is important for the formation of traits. And the level of gene activity is determined, firstly, by the nucleotide sequences inherited from parents, and secondly, by lifetime influences that change the activity of genes.

At the basis of lifetime changes in gene activity, among other mechanisms, there are those that make it possible to transfer changes in activity to offspring without the appearance of mutations in the gene. These mechanisms are called epigenetic, that is, "built on top" of the genetic ones. One of these mechanisms is methylation, the chemical modification of cytosine by attaching a methyl group to it with special enzymes. Methylation is preserved during cell division in the body, maintaining their tissue specificity.

For at least some traits, maintenance of methylation acquired in vivo by the parent has been shown in the offspring. For example, when developing fear in response to a certain smell, combined with an electric shock, a change in the methylation of the regulatory region in the olfactory receptor gene responsible for the perception of this smell was found in male mice, as a result of which the activity of the gene (and sensitivity to smell) increases.

In the children and grandchildren of these males, the level of methylation was also changed for the same gene, but not for the genes of other olfactory receptors. The press wrote that these descendants inherited a fear of smell, but this is not true. They inherited the ability to smell very low concentrations of a substance that proved dangerous to their mouse grandfather.

At the same time, epigenetic inheritance is reversible: methylation can be changed in vivo "in the opposite direction" in any generation. This distinguishes it from changes in traits under the influence of "classical" mutations that change nucleotide sequences, and not "supranucleotide" marks. What exactly traits can be transmitted epigenetically to offspring and what are the mechanisms of such epigenetic inheritance remains to be studied. And then, freed from politicized components, it will be possible to say "this is true, but in part."

Every now and then, in various sources, the myth that "the pig is genetically closer to humans than the chimpanzee" pops up, and this delusion is very stable.

Partly, due to the fact that the internal organs of a pig are very well suited for transplantation to humans. And Bernard Werber added fuel to the fire with his rot "Father of Our Fathers" (but there, one must understand, pure fantasy).

But what do geneticists think about this, how genetically close are pigs and humans?

Vladimir Alexandrovich Trifonov: The genome homology numbers have a rather low value, it all depends on what we are comparing with: whether we take into account structural changes in the genome, whether we take into account repeated sequences, or whether we are talking only about substitutions in coding regions.

As a comparative cytogeneticist, I can say that the evolution of porcine karyotypes was accompanied by a large number of rearrangements - even from a common ancestor with ruminants and cetaceans, 11 breaks and 9 inversions separate the porcine, plus 7 mergers and three inversions occurred in the pig line after the separation of peccaries. When we build molecular phylogenies based on sequencing data, the pig is never related to humans, there are many such data that can be cited and are much more accurate and reliable than general estimates of molecular differences. There are hundreds of thousands of differences between the pig and human genomes, so special programs are used to evaluate them, which, based on the similarity and difference of many features, build phylogenetic trees. The position on the phylogenetic tree just reflects the degree of similarity or difference between species.

Phylogeneticists have their difficulties and their controversies, but today few people doubt some of the basic ideas. For example, here are three modern papers where phylogenies were built by different groups (who are generally recognized experts in this field), based on a set of characters taken from DNA sequences:

Conrad A. Matthew et al. Indel evolution of mammalian introns and the utility of non-coding nuclear markers in eutherian phylogenetics. Molecular Phylogenetics and Evolution 42 (2007) 827–837.

Olaf R. P. Bininda-Emonds et al. The delayed rise of present-day mammals. Nature, Vol 446|29 March 2007.

William J. Murphy et al. Using genomic data to unravel the root of the placental mammal phylogeny. Genome Res. 2007 17: 413-421.

In all published phylogenies (see the figure below), the pig firmly takes its place among artiodactyls, and man "does not jump out" from the order of primates, i.e. the data obtained from the analysis of different DNA sequences give the same answer to this question, confirming in this question the phylogenies constructed according to morphological characters as early as the 19th century.

The figure shows that the pig is farther from the person than the mouse, rabbit and porcupine. Source: William J. Murphy et al. Using genomic data to unravel the root of the placental mammal phylogeny. Genome Res. 2007 17:418.

Mikhail Sergeevich Gelfand: to be honest, I won’t say right away about the exact % of DNA matches, and it’s not very clear what that would mean: in the genes? in intergenic intervals? most of the genome of a pig with a human simply does not align (unlike chimpanzees), it makes no sense to talk about% matches there. In any case, a pig is further from a person than a mouse. But who is close to pigs is whales (although they are even closer to hippos).

Question. Konstantin Zadorozhny, editor-in-chief of the magazine for teachers "Biology" (Ukraine): In the e-book of the respected S.V. I personally met the information before, but it was practically not covered in popular publications). Accordingly, the question is for one of the experts. At what stage of human evolution (early hominids, australopithecines, early homos, etc.) did this chromosomal aberration occur? Is it possible to determine this?

Answer. Vladimir Aleksandrovich Trifonov: I will be happy to answer your question, since the fusion of the chimpanzee and human ancestor chromosomes (corresponding to the chimpanzee PTR12 and PTR13 chromosomes) is indeed the last significant event that changed the human karyotype.

Let's start with the ancestor of great apes - the data of comparative genomics indicate that these two elements of the karyotype were acrocentric, and it was in this unchanged form that they were preserved in the orangutan.

Further, in the common ancestor of humans, gorillas, and chimpanzees, a pericentric inversion occurs, turning one of these elements into a submetacentric (this element corresponds to the chimpanzee PTR13 chromosome and the gorilla GGO11 chromosome). Then, in the common ancestor of humans and chimpanzees, another pericentric inversion occurs (in the homologue of the PTR12 chromosome of the chimpanzee), turning it into a submetacentric.

And, finally, the last event in the Homo line is the fusion of two submetacentrics with the formation of the human chromosome HSA2. This is not a Robertsonian fusion (centric), but a tandem fusion, while the PTR12 centromere retains its function, the PTR13 centromere is inactivated, and ancestral telomeric sites are found at the point of tandem fusion (Ijdo et al., 1991).

According to the time of formation of the human HSA2 chromosome, one can only say that the fixation of this rearrangement occurred after the divergence of the human-chimpanzee lines, i.e. not earlier than 6.3 million years ago.

I don't think the great apes have an increased frequency of Robertsonian translocations. They have very conservative karyotypes that change little over millions of years; during this time, dozens of significant transformations took place in the karyotypes of species of other taxa. There is evidence from clinical cytogenetics indicating a frequency of 0.1% in human meiosis (Hamerton et al., 1975). However, genome analysis shows that such rearrangements were not fixed in the human lineage.

Question. Alexey (letter to the Editor): Questions arise in the course of reading lectures on genomics for Phystech. Gene not defined...

Answer. Svetlana Aleksandrovna Borinskaya: It was easy to define a gene when not much was known about it. For example, "a gene is a unit of recombination", or "a gene is a section of DNA encoding a protein", "One gene - one enzyme (or protein)", "One gene - one trait".

Now it is clear that the situation is more complicated with both recombination and coding. Genes have a different structure, sometimes quite complex. One gene can encode many different proteins. One protein can be encoded by different DNA fragments located at a great distance in the genome, the products of which (RNA or polypeptide chains) are combined as they mature into one polypeptide.

In addition, the gene contains regulatory regions. And there are genes that do not code for proteins, but only for RNA molecules (besides the well-known ribosomal RNA, these are RNA molecules that are part of other molecular machines, recently discovered microRNA and others
RNA types). Therefore, there are now many definitions of what a gene is. The gene is a concept that is difficult to fit into one short, all-encompassing definition.

Answer S.B.: The genome is DNA. Or a complete set of DNA molecules of an organism (in a single cell) = genome.

However, we do not mean cells in which DNA rearrangements occur during development (such as cells of the immune system in mammals or animal cells in which "chromatin diminution" occurs - the loss of a significant part of DNA during development).

Answer S. B.: E. coli is the most studied bacterium, but even for it, functions are still not known for all genes. Although the amino acid sequence of the protein can be "derived" from the nucleotide sequence of the gene. For well-studied bacteria, for about half of the genes, the functions of the proteins they encode are known. For some genes, experimental confirmations of functions have been obtained, for some, predictions are made on the basis of the similarity of the protein structure with other proteins with known functions.

Question. Alexei: Do I understand correctly that the number of nucleotides in a gene is different for each gene? There is no pattern here.

Answer S.B.: Quite right.

Question. Alexei: Can different genes have exactly the same nucleotide sequence, but differ only in location?

Answer S.B.: There are probably no absolutely identical genes. But there are genes located in different parts of the genome with a very similar nucleotide sequence. Only they are called not "similar", but "homologous". These genes resulted from the duplication of an ancestral gene. Over time, nucleotide substitutions accumulate in them. And the closer the time of duplication is to us, the more similar the genes are. Gene duplications are found in all organisms, from bacteria to humans.

At the same time, different genes in different people can be contained in different numbers of copies. The number of copies can influence the activity of the corresponding gene products. For example, a different number of genes for certain cytochromes affects the rate of metabolism and excretion of drugs from the body and, accordingly, it is recommended to use different doses.

Question. Alexey: I would also like to hear the opinion of specialists regarding the materials provided by Garyaev (meaning the so-called "wave genome" theory). He claims that his experiments are confirmed experimentally in laboratories. Is it so. What can you say to this?

Answer S.B.: You can also say whatever you like. But the scientific world will pay attention to your claims only if they are published in peer-reviewed scientific journals, and even presented with a description of the details of the experiment, allowing it to be repeated.

Mr. Garyaev does not publish his "discoveries" in scientific journals, he only tells journalists. There is no data on his "experiments", only his words. Let at least the laboratory journal show with a detailed record of the conditions and results of the experiments.

- What discoveries, achievements in the field of human evolutionary genetics do you consider the most important over the past 10 years? 20 years? 50 years?

In the evolutionary genetics of both humans and other species, the most important results came from DNA analysis - it introduced significant changes in the ideas about the evolutionary tree. For humans, this analysis proved that all modern humans are descended from a single ancestral group that lived in Africa.

Important: the migration paths drawn on the basis of DNA analysis of modern populations do not pass through mountains and rivers, but through populations (who now live there, and their ancestors could have lived elsewhere before). To link migration routes to geographic features, we need data on ancient DNA.

In different sources, you can see different numbers characterizing the proximity of the human and chimpanzee genomes - 98.5% or, for example, 94%. What does this spread of numbers depend on, and yet, which is more correct?

The spread of numbers depends on what type of differences between genomes are used. Nucleotide "texts" can differ in substitutions of individual letters (the so-called single nucleotide polymorphisms, the English abbreviation SNP, Single Nusleotide Polymorphism), the number of repeating fragments (CNV, Copy Number Variation), the order or orientation of large fragments can be changed (these changes have long been known as changes in the position of chromosome fragments).

Genomes may differ in the presence of inserts or the loss of fragments of different sizes. In addition, two simian chromosomes in humans are combined into one, so we have 46 chromosomes, while chimpanzees have 48.

It is difficult to indicate all these various restructurings in one figure, therefore, depending on what exactly was taken into account, the numbers are different. But when any type of difference is accounted for, the pattern of similarities between species is the same - the chimpanzee is closest to humans, then the gorilla, then the orangutan, and so on.

These few percent that distinguish the human genome from the chimpanzee genome - what is their "physical meaning"? What are these genes, what are their functions?

When comparing the genomes of humans and chimpanzees, mutations were identified that "made us human." These are the mutations that appeared in the human lineage and led to important changes in biochemical processes, body shape, or changed the timing of the maturation of certain systems.

However, this "physical meaning" has a very small part of the differences. Basically, the differences are due to the random accumulation of "neutral" mutations that do not manifest themselves in any way in the appearance or biochemical characteristics of their owners.

Part of the "meaningful" differences is associated with the accumulation of adaptive mutations, and in the chimpanzee genome - some mutations, in the human genome - others. Among the known changes are mutations that inactivate some "unnecessary" genes for humans. For example, inactivation of the keratin gene, a protein that is part of the hair, is associated with the absence of hair on the human body. Inactivation of olfactory receptor genes in humans is associated with a reduced survival role of the sense of smell. An important change is the inactivation of the gene for one of the proteins that is part of the masticatory muscles. The weakening of the powerful masticatory muscles attached to the bones of the skull made it possible to "liberate" it from the functions of a frame for these muscles and increase the size of the cranium, and, accordingly, the size of the brain.

Mutations in genes associated with brain size and function are particularly interesting. Human ancestors accumulated mutations in the genes that control brain size, and selected those that led to an increase in its size.

An important class of mutations that distinguish humans from other primates are changes in the genes of regulatory proteins. These proteins regulate the work of entire groups of other genes, and a change in one such protein leads to significant changes in the work of gene ensembles. By changing these proteins, it is possible, due to a small number of mutations, to achieve significant changes in the structure and functions of various organs.

Differences between human and primate genomes have already been "inventoryed", but the meaning of these differences is still clear only for a small fraction of mutations.

How do you feel about the proposals of some researchers to include chimpanzees and gorillas in the genus Homo based on genetic data?

Positively. Formally, at the level of DNA, we differ less from our primate brothers than two species of rats. Although in appearance and in lifestyle they differ much more.

Probably a naive question, but will it be possible in the foreseeable future by means of genetic engineering to “make a human out of a monkey”? What difficulties stand in the way of solving such a problem?

What for? we already are - nature has already done. I think that it is unethical to make a factory for the production of something from half-humans, half-monkeys (it is possible to obtain various useful substances from microorganisms or tissue cultures), and philosophical problems cannot be solved in this way. It is better to preserve the natural populations of our relatives.

Another science fiction question: is it possible in the foreseeable future to solve a problem like cloning a Neanderthal?

Cloning from existing DNA fragments is impossible - they are very short, you cannot sew them into a single whole. Synthesis of DNA based on the obtained information about the sequence of the Neanderal genome is hardly possible so far. When determining the nucleotide sequence of ancient DNA, there is a high probability of erroneous "reading" due to the fact that over thousands of years chemical modifications accumulate in DNA, which can be mistaken for real mutations. In addition, in a test tube, DNA is synthesized in fragments of several thousand nucleotides in size. When assembling these fragments, errors also occur. As a result, the number of errors will be so high that the system will not be viable. But there is still the stage of introducing DNA into the cell. And some more technical difficulties - for example, what to do with the level of DNA methylation.

DNA methylation is a method of chemical modification of certain nucleotides (hinging a methyl group with special enzymes). Methylation can affect the activity of genes, the recognition of DNA by enzymes (for example, by restriction enzymes, which, depending on the presence or absence of a methyl group, cut or do not cut certain sequences) and more.

You can read more about the problems associated with the study of ancient DNA in this article.

Unfortunately, the Russian Internet is full of all sorts of disinformation (for example, one regularly encounters ranting that genetically closest to a person is not a chimpanzee, but a pig ...). What are the most common myths, misconceptions about human genetics?

About pigs - a well-known myth. Insulin used to be obtained from a pig, since some of the proteins we have with pigs are really similar. And other proteins are more similar to other animal species. Most of all coincidences - I repeat - with chimpanzees. But more is known about the pig - that's the old information circulating.

The most common misconceptions are associated with complete illiteracy, with the fact that many are not even familiar with the compulsory school course of genetics.

Here is an example - a response to our lecture on the inheritance of blood groups. If an illiterate dad read a page in a school textbook about dominant and recessive traits, there would be no life tragedy:

"The material is not only interesting, but also understandable even for a primary school student. I have been interested in this topic since my father (who, like my mother, is Rh positive, but unfortunately I turned out to be negative) said me that because of this I am not his daughter, accused my mother of all mortal sins and left us. So, dear dad, you are deeply mistaken. You are wrong !!! "(From the site http://www. bio.fizteh.ru/student/files/biology/biolections/lection03.html)

The progenitor of domestic pigs is a wild boar, belonging to the genus of artiodactyl non-ruminants. Currently, these farm animals are bred in many countries of the world. But they are most popular in Europe, Russia and the states of East Asia.

Appearance of a pig

From their ancestors, wild boars, domestic pigs do not differ too much. The only thing is that piglets are not usually covered with such thick wool. The anatomy of a pig and a wild boar is almost identical.

Distinctive features of domestic piglets are:

  • compact body;
  • legs with hooves;
  • bristled hairline.

An elongated muzzle ending in a heel, which, when searching for food to loosen the soil, is, of course, also one of the main characteristic features of a pig. In the photo below you can see how convenient it is for piglets to use this organ of theirs even when kept at home. It is a cartilaginous movable disc.

The shape of the pig's head can, among other things, determine its appearance. In representatives of meat breeds, it is somewhat elongated. In greasy piglets, this part of the body has a more rounded shape.

Pig Anatomy: Musculoskeletal System

Piglets belong to the class of mammals. The skeleton of these animals is represented by about 200 bones. In this case, the following varieties are distinguished:

  • long tubular;
  • short;
  • long curved;
  • lamellar.

The pig skeleton itself consists of several sections:

  • skulls;
  • body and tail;
  • limbs.

The muscular system of the pig is represented by smooth muscles and skeletal muscles. The bones in the body of these animals connect forming joints. In total, pigs have several unpaired and about 200-250 paired muscles.

Digestive and excretory system

Piglets are almost omnivores. And the digestive system of pigs is developed, of course, very well. Its main departments are:

  • oral cavity;
  • pharynx and esophagus;
  • single chamber stomach;
  • large and small intestine;
  • rectum;
  • anus.

For filtering blood and neutralizing harmful substances in pigs, as in any other mammals, the liver is responsible. The stomach in these animals is located in the left hypochondrium, and the pancreas - in the right.

genitourinary system

One of the absolute advantages of pigs as farm animals is their high fertility. The reproductive system of boars is represented by the following organs:

  • scrotum and testis;
  • duct and spermatic cord;
  • urogenital canal;
  • penis;
  • a special skin fold that covers the penis - the prepuce.

The reproductive system of the female pig is represented by the following organs:

  • ovaries;
  • fallopian tubes;
  • uterus and vagina;
  • external organs.

The sexual cycle in a pig can last from 18 to 21 days. These animals bear cubs for 110-118 days. One sow can have up to 20 babies. This is even more than that of rabbits famous for their fertility.

The genitourinary system of the pig is also represented by:

  • paired kidneys;
  • ureters;
  • bladder;
  • urethra.

In males, the urethra, among other things, conducts sexual products. In pigs, it opens into the vestibule of the vagina.

Nervous system

Pigs are highly developed animals. It is believed that they are similar in intelligence to dogs. These animals, for example, can be easily taught to carry out various kinds of commands. Like dogs, pigs are able to return from afar to the places where they once lived.

The nervous system of these animals is represented by:

  • brain and spinal cord with ganglia;
  • nerves.

The brain of these animals has two hemispheres with convolutions and is covered with a bark. Its mass in pigs ranges from 95-145 g. The length of the spinal cord in these animals can be 119-139 cm.

The cardiovascular system

Like other mammals, the central organ of blood circulation in pigs is the heart. It has a conical shape and is divided into right and left halves by a longitudinal partition. Rhythmically contracting, the pig's heart drives blood throughout its body. Each half of the animal heart, in turn, is divided by transverse valves into a ventricle and an atrium.

The blood of pigs consists of plasma and erythrocytes, platelets and leukocytes floating in it. From the heart, it flows through the animal organism through the arteries, and returns to it through the veins. Also, the circulatory system of the pig is represented by capillaries, through the walls of which oxygen enters the tissues.

All kinds of foreign particles and microorganisms are neutralized in the body of these animals in the lymph nodes.

Features of the structure of the skin of pigs

The thickness of the skin of piglets can vary between 1.5-3 mm. In purebred pigs, this figure may even be equal to only 0.6-1 mm. At the same time, the subcutaneous layer in piglets contains a very large amount of fat and can reach a huge thickness.

Mature males have a shield on the sides of the shoulder girdle and chest, consisting of compacted bundles with fatty pads. This formation protects wild boars during fights during the period of sexual hunting.

Rigid bristle hairs on the skin of pigs alternate with soft ones. The density of the hairline in piglets of different breeds may vary. In most cases, bare piglets are, of course, bred on farms. But there are also breeds whose representatives are covered with thick hair, about the same as wild boars.

Analyzers, organs of hearing and vision

The circulatory system of the pig is thus very well developed. The same applies to other organs of piglets. For example, the sense of smell of pigs is simply excellent.

The organ responsible for the perception of smells in these animals is located in the nasal passage and consists of:

  • olfactory epithelium;
  • receptor cells;
  • nerve endings.

The sense of touch in pigs is carried out by receptors of the musculoskeletal system, mucous membranes and skin. The organs of taste in these animals are papillae located in the oral mucosa. The eyeballs in pigs are connected to the brain by the optic nerve.

The ears of these animals consist of the following sections:

  • cochlear part;
  • pathways;
  • brain centers.

Similarities and differences between pigs and humans

Humans, as everyone knows, belong to the class of primates and are descended from apes. Purely outwardly, a person, of course, most of all resembles this particular animal. The same applies to the structure of internal organs. However, in terms of physiology and anatomy, a person is quite close to a pig.

For example, like humans, piglets are omnivores. It is believed that they were once tamed precisely because of this. Wild boars willingly ate the remains of human food. The only difference between humans and pigs in this regard is that the latter have fewer bitter taste receptors in their mouths. Piglet perceives sweet and bitter in a slightly different way than a person.

As you know, the structure of the pig's heart is not much different from the human heart. Doctors even try to use piglets in this regard as donors for both humans and monkeys. The heart of piglets weighs 320 g, in humans - 300 g.

Very similar to human and pig skin. These animals, like people, can even sunbathe. Similar in structure to humans and pigs as well:

  • eyes;
  • liver;
  • kidneys;
  • teeth.

The yellow press sometimes even flashes information that sometimes sows in the United States and China are used to carry human embryos.

What do scientists think

People have been raising piglets for a long time. And the anatomy of pigs is studied, of course, just fine. However, there is no clear answer to the question of why piglets and primates are so similar, unfortunately. In this regard, there are only a few untested hypotheses. For example, some scientists believe that the pig itself once descended from a primate.

There is even confirmation of this incredible hypothesis. On the island of Madagascar, researchers have found fossils of lemurs with a long muzzle with a snout. Like pigs, these animals once tore the ground with their noses in search of food. At the same time, instead of hooves, they had a five-fingered hand, like a person's. Yes, and in the embryos of modern pigs, oddly enough, there is the laying of a five-fingered hand and muzzle, like a primate.

Ancient legends are also a kind of confirmation that piglets were once primates. For example, in one of the legends of the inhabitants of the island of Bot, it is stated that in ancient times the hero Kat made people and pigs according to the same pattern. Later, however, the piglets wanted to have their own differences and began to walk on four legs.

Diseases of humans and pigs

Scientists have noticed that the similarity between humans and pigs is not limited to the anatomical structure of the organs. Almost the same in primates and piglets and diseases. For example, in pigs, as in humans, Alzheimer's disease can be diagnosed in old age. Piglets are also very often obese. Can be observed in these animals and Parkinson's disease. The pig in the photo below suffers from just such a disease.

transgenic animals

The heart and other organs in piglets and humans are similar. However, they are not identical. Experiments on the transplantation of pig organs in humans have ended, unfortunately, in failures due to tissue rejection. To solve this problem, scientists began to breed special transgenic pigs. In order to get such piglets, two human genes are introduced into the embryo and one pig gene is turned off.

Many scientists believe that experiments to breed transgenic pigs in the future may actually help solve the problem of tissue rejection during organ transplants. By the way, there is already evidence for this. For example, in 2011, Russian surgeons successfully transplanted a heart valve from a transgenic pig into a patient.

similarity at the genetic level

The anatomy and physiology of pigs is such that, according to some scientists, they are an accurate biological model of a person. According to the structure of DNA, monkeys are, of course, closest to humans. For example, the differences in human and chimpanzee genes are only 1-2%.

But pigs in terms of DNA structure are quite close to humans. The similarity between human and pig DNA is, of course, not so great. However, scientists have found that in humans and piglets, some types of proteins are very similar in composition. That is why piglets were once actively used to obtain insulin.

Recently, in the scientific world, such a topic as growing human organs inside piglets has caused a lot of controversy. Purely theoretically, carrying out such procedures is nothing impossible. After all, the human and pig genomes are indeed somewhat similar.

To obtain organs, human stem cells can simply be placed in a sow's egg. As a result, a hybrid will develop, from which in the future not a full-fledged organism will grow, but only one organ. It can be, for example, the heart or spleen.

Of course, organs grown inside pigs could save the lives of many people. However, many scientists are opposed to this method. Firstly, conducting such experiments, of course, is inhumane in relation to the pigs themselves. Secondly, it is believed that the cultivation of human organs in pigs could lead to the emergence of new genetically modified pathogens that could kill millions of people.

pig man genome

The blood of pigs is biologically 70% identical to human blood. This made possible a very interesting experiment. The scientists took a pregnant sow and injected the embryos with white human blood containing hereditary information. The animal's pregnancy ended in a successful birth.

In the blood of the newly born piglets, the researchers subsequently found cells containing large sections of both human and porcine chromosomes. This, of course, became a real sensation in the scientific world. Among other things, such cells in the body of piglets were also resistant. That is, they persisted for a long time after birth. Simply put, for the first time, scientists have obtained a stable human-pig genome. Of course, there were few such cells in the body of the test pigs, and the animals were in no way similar to humans. However, the resulting genome contained more than a third of human material.

Other research scientists

Be that as it may, the anatomy of pigs is well studied, and the idea of ​​using these animals as donors looks quite attractive. Most scientists at the same time believe that there is nothing impossible in this. Researchers in this regard already have quite serious developments. For example, scientists managed to find out that nerve cells taken from the body of pigs are capable of putting paralyzed people on their feet.

Very high-quality contact lenses are already made from porcine collagen today. Cartilage cells from piglets' ears are used to grow artificial breasts. Scientists have also created a pig that produces omega-3 fatty acids that are useful for the human heart.